1. Field of the Invention
The present invention relates to a light source device having a plurality of light emitting elements arranged in a linear configuration, and arranged on the side surface of a light guiding plate for making a planar light source device. Also, the present invention relates to a planar light source device.
2. Description of the Related Art
There is a planar light emission light source having a light guiding plate and a linear light source device arranged on the side surface of the light guiding plate (for example, see Patent Reference 1) as the backlight light source of the liquid crystal display panel for use in cell phones or digital cameras, etc.
The linear light source device includes a printed circuit board having a slender rectangular-shaped wiring pattern formed thereon, light emitting elements arranged in plurality separated from each other along the longitudinal direction of the printed circuit board on the printed circuit board and connected with the wiring pattern of the printed circuit board, reflectors having a slope surface arranged on one side and the other side in the longitudinal direction of the various light emitting elements, respectively, and a sealing resin for sealing the various light emitting elements.
For the linear light source device, when thermosetting is carried out for the sealing resin, the linear light source device wraps convex downward (in the direction to the surface on the side opposite to the surface of the printed circuit board where the light emitting elements are assembled). As a result, close contact property on the light guiding plate degrades, and the light incidence efficiency to the light guiding plate decreases.
In the prior art, a linear light source device is arranged so that it is pressed on the light guiding plate, and such pressing corrects the warp of the linear light source device.
According to Patent Reference 2, the reflector arranged for a light emitting element and the reflector arranged for the adjacent light emitting element are not arranged continuously in order to prevent warp of the linear light source device. Instead, they are separated from each other by arranging a groove. The groove can relax the stress generated due to contradiction of the sealing resin, and it can prevent warp.
According to Patent Reference 3, for the LED package having LEDs, and a substrate having a recession accommodating the LEDs, a convex portion is arranged on the upper surface of the substrate. By arranging such convex portion, when the LED package is arranged on the side surface of the light guiding plate, it is possible to carry out positioning at a high precision.
Patent Reference 1: JP-A-2004-235139
Patent Reference 2: JP-A-2006-120691
Patent Reference 3: JP-A-2004-363537
However, when the linear light source device is arranged so that it is pressed on the light guiding plate to correct the warp of the linear light source device, there is a problem that the light guiding plate degrades due to the heat generated by the linear light source device. Also, the method described in Patent Reference 2 has insufficient effect in preventing warp.
The LED package described in Patent Reference 3 is not a linear light source device, and the convex portion arranged on the upper surface of the substrate cannot solve the problem.